Many different types of data storage systems exist and are being used to store data cartridges at known locations and to retrieve desired data cartridges so that data may be written to or read from the data cartridges. Such data storage systems are often referred to as "juke box" data storage systems, or "autochanger" data storage systems, particularly if they can accommodate a large number of individual data cartridges.
A typical juke box data storage system may include one or more different types of cartridge receiving devices for holding the various data cartridges. For example, one type of cartridge receiving device may comprise a cartridge storage rack or "magazine" while another type of cartridge receiving device may comprise a cartridge read/write device. The cartridge storage racks or magazines serve to provide storage locations for the data cartridges and are often arranged so that they form one or more vertical stacks, although other configurations are possible. The cartridge read/write device may be located at any convenient location within the data storage system.
The data storage system may also be provided with a moveable cartridge picker assembly or simply "picker" for transporting the data cartridges between the various cartridge receiving devices, e.g., between the cartridge storage racks and the cartridge read/write devices. A typical picker may also be provided with a cartridge plunge mechanism or "thumb" assembly for engaging the various data cartridges contained in the cartridge receiving devices and for drawing them into the picker. A picker positioning system associated with the cartridge picker assembly may be used to move the cartridge picker assembly along the various cartridge receiving devices.
Data storage systems of the type described above are usually connected to a host computer system which may be used to access or store data on the data cartridges. For example, if the host computer system issues a request for data contained on a particular data cartridge, a control system associated with the data storage system will actuate the picker positioning system to move the picker assembly along the cartridge storage racks until the picker assembly is positioned adjacent the desired data cartridge. The cartridge plunge mechanism or "thumb" assembly associated with the picker assembly may then remove the data cartridge from the cartridge storage rack and draw it into the picker assembly. The picker positioning system may then be actuated to move the picker assembly to the appropriate cartridge read/write device. Once properly positioned adjacent the cartridge read/write device, the thumb assembly may insert the selected data cartridge into the cartridge read/write device so that the host computer may thereafter read data from or write data to the data cartridge. After the read/write operation is complete, the thumb assembly may be actuated to remove the data cartridge from the cartridge read/write device. The picker assembly may thereafter return the data cartridge to the appropriate location in the cartridge storage rack.
A typical cartridge plunge mechanism or "thumb" assembly is usually slidably mounted inside the picker and is provided with a thumb actuator system to move the thumb assembly toward and away from a cartridge access end of the picker. For example, if it is desired to retrieve a data cartridge from a cartridge receiving device, the thumb actuator system moves the thumb assembly toward the cartridge access end of the picker so that the thumb assembly can engage or "grab" the data cartridge. A finger assembly may be pivotally mounted on the thumb assembly to engage a notch in the data cartridge to selectively engage and disengage the data cartridge.
Thereafter, the thumb actuator system may retract the thumb assembly and engaged data cartridge into the picker. To load the data cartridge into a cartridge receiving device the thumb actuator moves the thumb assembly and data cartridge toward the cartridge access end of the picker, and inserts the data cartridge into the cartridge receiving device.
Previous tape biasing mechanisms include springs having a solid, unmoving tip, attached to the picker 12 with separate hardware such as nuts and bolts. For example, an Overland Data LibraryXpress LXB.RTM. data storage system employs a metal leaf spring having a solid plastic tip. The picker frame has a threaded stud extending from the outside of the frame which passes through a hole in the end of the leaf spring, and a washer and nut are screwed to the threaded stud to fasten the leaf spring to the outside of the picker. A solid plastic tip is connected to the leaf spring using sheet metal clips and extends into the picker through an access hole. The solid plastic tip is relatively short (e.g., the height is less than the width) and has a slight slope or bevel, allowing a specific data cartridge to pass by it into the picker.
However, solid spring tips have several disadvantages, such as being limited to a specific size and type of data cartridge. Solid spring tips also cause undesirable wear on the data cartridge and have a relatively short life span due to friction. The solid spring tip also tends to smudge or tear labels on the data cartridge, reducing legibility. Furthermore, the friction against the data cartridge and its label cause dust and debris in the picker which can cause errors.
A solid spring tip can be carefully optimized for a particular size and type of data cartridge to properly engage the cartridge and to minimize friction between the selected materials, but the picker is limited to that specific data cartridge. Changing the material of the data cartridge can lead to an undesirably high level of friction. Changing the size of the data cartridge can also increase the friction to the point of causing errors. In the extremes, the solid spring tip may either have so much friction with the data cartridge that it binds, or may wear down to the point that it does not apply sufficient force to bias the cartridge. The solid spring tip designed for a specific cartridge may also be too short to engage a thinner cartridge.
Furthermore, the construction and assembly of prior designs requires additional fasteners to connect the spring tip to the spring, or the spring to the picker, increasing the part count and complexity and reducing the potential accuracy and reliability of the finished assembly. The need for additional fasteners also increases the difficulty of assembly.
Consequently, a need exists for a cartridge referencing spring to bias multiple sizes and types of data cartridges inside a picker. In particular, a need exists for a cartridge referencing spring which is effective with different sizes and types of data cartridge and which minimizes friction with the data cartridge to reduce damage. A need further exists for a cartridge referencing spring which is simple and easy to attach to the picker, which does not require additional mounting hardware but which stays firmly affixed and positioned on the picker.